The present invention is directed to hardening ammonium nitrate without affecting other important physical properties.
A problem in the ammonium nitrate art is the competing need for porosity versus the need for hardness. This is especially true for ammonium nitrate bodies that can be used for explosive applications. Bodies of ammonium nitrate means but is not limited to formulations of ammonium nitrate, physical forms, such as prills, granules, or said prills and/or granules in an emulsion, and compositions wherein ammonium nitrate is a major component. Ammonium nitrate may be used for other applications such as fertilizers, wherein porosity is not an important property, in fact, it is undesirable. Hardness is important for fertilizers since hardness is related to the leaching rate of the fertilizer into the soil. Therefore, hardness is important for both explosive and fertilizer applications. Those skilled in this art know that hardening or the lack thereof of ammonium nitrate bodies for the purposes of storage and/or for their transportation to end-use destinations has been a problem in this art for sometime.
Hardness for ammonium nitrate (AN) bodies is generally defined by crushing strength, which is tested by providing a constant load on the body until the body is crushed or cracked. Friability is also a measure of hardness. Friability, as determined by the method described hereinbelow, is the characterization of the hardness of the outside surface of the body. Porosity may be determined by characterizing particle density as can be measured by mercury pyknometry.
The present invention advances the ammonium nitrate art with the application of polymers, organic, inorganic and/or combinations thereof to produce a hardened ammonium nitrate previously unknown to this art. The ammonium nitrate of the present invention may be used for any application where hardness is important. This is especially true for the explosive and the fertilizer arts used in the body of a prill.